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T. E. DROHAN. QUICK BREAK ELECTRIC SWITCH.

No. 600,523. PatentedI/Iar. 15,1898.

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iran STATES Parnu f Fries,

THOMAS E. DROHAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS da HALSKE ELECTRIC COMPANY OF AMERICA, OF SAME PLACE.

QUICK-BREAK ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 600,523, dated March 15, 1898.

Application filed November 13,1897. Serial No. 658,362. (No model.)

To @ZZ whom t may concern:

Be it known that I, THOMAS E. DROHAN, a citizen of the United States, residing at Chicago, Cook county, Illinois, have invented new and useful Improvements in Quick-Break Electric Switches, (Case N o. 125,) of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

My invention relates to improvements in quick-break electric switches, and has for its object the provision of a switch insuring the ready flow of current when the contacts thereof are engaged,while affording a sudden break when the switch is thrown, and means for diverting from the main contacts of the switch any arc which is liable to be formed therebetween.

In practice itis found, especially when currents of high tension are to be controlled, that it is desirable not only that the switch when thrown make a quick break, but that the said switch be provided with means for diverting the ilow of current from the main contacts at the moment of their separation, whereby any arc which is caused by breaking the circuit will be prevented from forming between and destroying or impairin g the said contact parts. It is desirable, however, that all tendency toward arcing between any portions of the switch be prevented as far as possible, since the contacts are thereby quickly deteriorated and their frequent renewal is necessitated.

The switch of my invention is designed to obviate the numerous difficulties hitherto eX- perienced in the operation of electric switches commonlyin use and maybe briellydescribed as consisting of a main and a secondary blade adapted to close the circuit between the main terminals of the switch, the movement of the said secondary blade depending upon that of the main blade and being provided in addition with an auxiliary contact part adapted to form the leaving contact of the switch at the moment the switch is opened,whereby any arc formed is diverted from the main contact parts. The auxiliary contact parts of the said switch preferably are formed of carbon.

My invention will be more readily understood by reference to the accompanying drawings, whereiny maintain the circuit therethrough.

Figure l is a plan view of the switch embodyin g my invention, said switch being closed. Fig. 2 is a side elevation thereof, showing the switch partially open, the circuit 5 5 being maintained through the secondary blade and the auxiliary contacts of the switch. Fig. 3 is a similar View, partially in section, showing the switch open and the circuit therethrough broken.

Similar parts are designated by the same letters of reference in each of the said igures of the drawings.

Upon a base a, formed of suitable insulating material, are mounted the main circuitterminals b and c. In the said terminal b the main blade d of the switch is pivotally mounted by means of the bolt b. The nuts b2 serve to compress the spring-washers b3, mounted upon said bolts, and secure a tight joint be- 7o tween the knife-blade and said circuit-terminal. The secondary blade e is also pivotally mounted in the circuit-terminal b, being provided with a pivotal bolt e. A stiff spring e2, coiled upon said bolt, engages the under side of the secondary blade, against the tension of which the said blade e is forced down- Ward and between the spring-clips of circuitterminal c. The secondary blade is provided with a trip c3, also mounted upon the bolt e', 8o l which is separate from the blade, but lits with in a recess e4 and is rearwardly acted upon by the eccentric part d of the main blade. t Connected with the circuit-terminal c are the l carbon blocks ff,mounted upon spring-strips f by means of screws, between which the cary bon contact part gis adapted to be forced and yieldingly held in position when the switch is closed and the secondary blade is in engagement with the circuit-terminal c. 9o

The engaging edges of the carbon contacts are slightly beveled in order that the contact part g may be readily forced between the carbons f f when the switch is closed, and the spring-mounting of the latter serves to firmly though yieldingly engage the carbons and The said carbon parts thus form an auxiliary electrical connection for the switch, and the same are disposed so that contact is last maintained roo between these auxiliary contacts when the switch is thrown. \Vhen the switch is closed,

and spring-washers forming the pivotall mounting of the blade. When it is desired to open the switch, the insulating-handle h is seized and the main blade is raised from the spring-clips, which causes the eccentric portion cl to engage the trip e3 of the secondary blade, thus in turn withdrawing the blade l from the spring-clips and at once snapping it into engagement with the main blade d.

end of the secondary blade, is so disposed as momentarily to make contact with the carbon blocks f f after said secondary blade is released from the spring-clips, in consequ ence of which any arc which may be formed is diverted to the carbon contact parts, and the main contacts of the switch are thus protected from injury in this respect.l The trip e3, being independent in its movement, is not snapped upward by the spring with the secondary blade, but remains in the position shown in Fig. 3.

Since the greater portion of the current is conducted by the main blade d, it is not essential that the secondary blade be provided with an extremely tight joint, in consequence of which the spring e2 is enabled to act with unimpai-red strength and is sufficiently strong to overcome the pressure between the carbon contacts. Immediately the second blade i-s released from the spring-clips by the action of the eccentric and trip a very sudden break is effected between the leaving or carbon contacts of the switch, which secures a minimum amount of arcing in the switch, and in consequence it is necessary to renew said contact parts only at infrequent intervals. An extremely efficient contact is maintained between the carbon contacts by means of the spring-mounting of the carbon blocks f f and the wedge action of the contact g when forced therebetween. This auxiliary contact, however, is so gaged that there is no appreciable tendency between the parts to stick or bind and thus impede the movement of the secondary blade. I consider this a distinct i-mprovement in the construction and operation of this class of switches, since when the ordinary spring-clips are used alone they must of necessity be adapted to produce a tight contact with the movable blades. As a consequence of this the secondary blade at the moment of separation from the clips starts practically from a condition of rest, having been but slowly withdrawn from said clips,

which frequently causes serious though momentary arcing between it and the principal terminal or clips.

In the form of switch shown the secondary blade and carbon contact are moving with considerable rapidity at the moment of iinal separation from their respective switch-contact parts, whereby the tendency toward arcing is minimized or wholly avoided.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination in an electric switch with a pivotally-mounted conducting-blade d, of a secondary blade e similarly mounted, a spring e2 associated with said secondary blade, circuit-terminals b c between which the said blades are adapted to complete an electrical circuit when the switch is closed, an eccentric part d carried upon and moving with the The carbon contact g, mounted upon the main blade, and a trip c3 associated with the secondary blade adapted to Vbe engaged by said eccentric part when the main blade is raised and positively actuate the secondary blade and secure its withdrawal from circuitterminal c, whereby the spring is permitted to actand suddenly open the circuit, substantially as described.

2. In a quick-break switch, the combination with the circuit-terminals b C, of a main and a secondary contact-blade de pivotally mou nted and adapted to close the circuit between said terminals, carbon blocks f f forming supplemental contact parts or terminals, carbon contact g mounted upon the secondary blade in position to engage said contact parts f f after the circuit is opened through the switchblades, and means'for suddenly disengaging the secondary blade and contact g from their respective circuit-terminals when the main blade is actuated to open the switch, substantially as described.

3. The -combination in a quick-break electr-ic switch, with acircuit-terminal b, of a main and a secondary blade or part d e pivotally mounted therein, spring-clips c forming a second circuit-terminal and adapted to receive v said blades, whereby the circuit is closed between said terminals, spring @2 associated with said secondary blade, carbon blocks f f yieldingly mounted in electrical connection with spring-clips c forming supplemental circuitterminals, carbon contact g mounted upon said secondary blade in position to maintain engagement with terminals f f after the circuit is open through the switch-blades, a trip e3 associated with the secondary blade, and an eccentric part d carried upon and moving with the main blade adapted'to actuatethe trip and remove the secondary blade from the spring-clips c, whereby the spring c2 is permitted to act and suddenly effect the separation of the carbon contact parts of the switch, substantially as described.

In testimony whereof I affix my signature, in the presence of two witnesses, this 2d day of November, 1897.

THOMAS E. DROHAN.

Witnesses:

A. L. LAWRENCE, GEQRGE L. CRAGG.

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